SnPxOy thin films were deposited on stainless steel substrates by electron-beam evaporation for use as anodes in thin-film lithium ion batteries. The thin films were heat-treated at various temperatures for 4 h, and their composition, microstructure, and electrochemical properties were characterized by Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD), cyclic voltammetry (CV), and AC impedance spectroscopy. The specific discharge capacity of the as-deposited SnPxOy thin film anode decreased rapidly to 12 mu Ah cm(-2)-mu m within 10 cycles. However, after heat treatment for 4h at 500 degrees C, it maintained a high specific discharge capacity of 136 mu Ah cm(-2)-mu m and excellent cyclability even after 300 cycles, in contrast to pure SnOx thin film. (C) 2012 Elsevier Ltd. All rights reserved.